<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        var year = parseInt(prompt("请输入年份"));
        if(
            year % 4 === 0 && year % 100 !==0 || year % 400 === 0){
                console.log(year+ "是闰年");
                
            }else{
                console.log(year+"不是闰年");
            }
        
       

    </script>
</body>
</html>